title: Rapid detection of resistance to pyrazinamide in Mycobacterium tuberculosis using the resazurin microtitre assay.
abstract: OBJECTIVE
  The resazurin microtitre plate assay (REMA) was evaluated to determine the susceptibility of Mycobacterium tuberculosis to pyrazinamide, and was compared with the broth microdilution method (BMM), the absolute concentration method (ACM) and pyrazinamidase (PZase) determination.
  
  
  METHODS
  Thirty-four M. tuberculosis clinical isolates (26 susceptible and 8 resistant to pyrazinamide) and reference strains M. tuberculosis H37Rv ATCC 27294 and Mycobacterium bovis AN5 were tested.
  
  
  RESULTS
  REMA and BMM showed 100% specificity and sensitivity when compared with ACM; BMM, however, demanded more reading time. The PZase determination assay showed 87.50% and 100% sensitivity and specificity, respectively.
  
  
  CONCLUSIONS
  All tested methods in this preliminary study showed excellent sensitivity and specificity for the determination of pyrazinamide susceptibility of M. tuberculosis, but REMA was faster, low-cost and easy to perform and interpret. Additional studies evaluating REMA for differentiating pyrazinamide-resistant and -susceptible M. tuberculosis should be conducted on an extended panel of clinical isolates.
authors.affiliation: Department of Clinical Analyses and Biomedicine, State University of Maringá, Maringá, Paraná, Brazil.
authors.forename: Paula Aline Zanetti
authors.initials: PA
authors.lastname: Campanerut
authors.forename: Luciana Dias
authors.initials: LD
authors.lastname: Ghiraldi
authors.forename: Fernanda Luisa Espinoza
authors.initials: FL
authors.lastname: Spositto
authors.forename: Daisy Nakamura
authors.initials: DN
authors.lastname: Sato
authors.forename: Clarice Queico Fujimura
authors.initials: CQ
authors.lastname: Leite
authors.forename: Mário Hiroyuki
authors.initials: MH
authors.lastname: Hirata
authors.forename: Rosário Dominguez Crespo
authors.initials: RD
authors.lastname: Hirata
authors.forename: Rosilene Fressatti
authors.initials: RF
authors.lastname: Cardoso
mesh_terms: D024881:Drug Resistance, Bacterial; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000191:economics / Q000379:methods; D009163:Mycobacterium bovis / Q000187:drug effects / Q000378:metabolism; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000302:isolation & purification / Q000378:metabolism*; D010078:Oxazines / Q000378:metabolism*; D011718:Pyrazinamide / Q000494:pharmacology*; D012680:Sensitivity and Specificity; D013997:Time Factors; D014376:Tuberculosis / Q000382:microbiology; D014966:Xanthenes / Q000378:metabolism*
chemical_list: D010078:Oxazines; D014966:Xanthenes; C005843:resazurin; D011718:Pyrazinamide